This directory contains files used in goanna builds from FFmpeg
(http://ffmpeg.org). The current files are from FFmpeg as of
Release 4.0.2
All source files match their path from the library's source archive.

Currently, we only use the vp8 and vp9 portion of the library, and only on x86
based platforms. If this changes, configuration files will most likely
need to be updated.

configuration files were generated as follow using the configure script:
./configure --disable-everything --disable-protocols --disable-demuxers --disable-muxers --disable-filters --disable-programs --disable-doc --disable-parsers --enable-parser=vp8 --enable-parser=vp9 --enable-decoder=vp8 --enable-decoder=vp9 --disable-static --enable-shared --disable-debug --disable-sdl2 --disable-libxcb --disable-securetransport --disable-iconv --disable-swresample --disable-swscale --disable-avdevice --disable-avfilter --disable-avformat --disable-d3d11va --disable-dxva2 --disable-vaapi --disable-vdpau --disable-videotoolbox --enable-decoder=flac --enable-asm --enable-x86asm --disable-cuvid --disable-cuda

config*:
replace: /HAVE_(MALLOC_H|ARC4RANDOM|LOCALTIME_R|MEMALIGN|POSIX_MEMALIGN)/d

config_unix32.h:
add to configure command: --disable-asm --disable-x86asm --cc='clang -m32'
replace: s/HAVE_SYSCTL 1/HAVE_SYSCTL 0/ and s/HAVE_MEMALIGN 1/HAVE_MEMALIGN 0/ and s/HAVE_POSIX_MEMALIGN 1/HAVE_POSIX_MEMALIGN 0/

config_unix32.h/config_unix64.h/config_unix64.asm:
replace: s/HAVE_SYSCTL 1/HAVE_SYSCTL 0

config_win32/64.h/asm:
add to configure command: --toolchain=msvc

Regenerate defaults_disabled.{h,asm} with:
$ grep -E ".*_(INDEV|OUTDEV|DECODER|ENCODER|DEMUXER|MUXER|PARSER|FILTER|HWACCEL|PROTOCOL|ENCODERS|DECODERS|HWACCELS|INDEVS|OUTDEVS|FILTERS|DEMUXERS|MUXERS|PROTOCOLS|BSF) 0" config.h | sort -u > ~/REPO/UXP/media/ffvpx/defaults_disabled.h
$ grep -E ".*_(INDEV|OUTDEV|DECODER|ENCODER|DEMUXER|MUXER|PARSER|FILTER|HWACCEL|PROTOCOL|ENCODERS|DECODERS|HWACCELS|INDEVS|OUTDEVS|FILTERS|DEMUXERS|MUXERS|PROTOCOLS|BSF) 0" config.asm | sort -u > ~/REPO/UXP/media/ffvpx/defaults_disabled.asm

All new decoders/muxers/encoders/... should be added in the list of dummy functions found in libavcodec/dummy_funcs.c
otherwise linkage will fail on Windows. On other platforms they are optimised out and aren't necessary.
The GNU comm utility is a useful tool to compare and extract only the changes.

To update the source tree, perform a diff on the files listed in FILES.
The diffs should typically apply to the ffvpx tree.
e.g. something like this would do:
Run in the ffmpeg original tree:
$ for i in `cat $PATH_CENTRAL/media/ffvpx/FILES`; do git diff $REV_LASTSYNC HEAD >> patch.diff; done
Then apply patch.diff on the ffvpx tree.

Compilation will reveal if any files are missing.
